Apparatus for detaching a tire from a vehicle wheel and the same method

ABSTRACT

An apparatus and method for detaching a bead of even a tire, the ratio of which sectional height to its sectional width is small and the rigidity of which side portions is high, from the rim edge of the wheel not by manual labor, but by mechanical operation, in a safe and efficient manner.  
     The present invention is characterized in that a tire bead separation shoe ( 1 ), which comprises a wedge portion ( 12 ) to engage with the rim edge (WR) of the wheel (W) with a tire (T) placed round that is mounted on a turntable (R) so as to shove between the rim edge and the tire bead (TB) and a tire bead fold-back portion ( 11 ), is arranged above the turntable such that it moves up and down, and a thrusting rod ( 4 ) with a claw ( 41 ) provided at its tip end portion is operated when the said wedge portion ( 12 ) is shoved between the tire bead (TB) and the rim edge (WR) of the wheel so as to shove said claw ( 41 ) between the tire bead and the rim edge and to mount a part of the tire bead as squeezed out of the wheel by the claw onto the bead fold-back portion ( 11 ) while the turntable is revolved so as to smoothly detach the whole circumference of the tire bead (TB)from the rim edge of the wheel (W).

TECHNICAL FIELD

[0001] This invention relates to an improvement on the replacementtechnique of a tire from the vehicle wheel, in more details, pertainingto such apparatus that enables the bead of even a tire, the ratio ornominal aspect ratio of which sectional height to the sectional widththereof is small, said nominal aspect ratio being expressed with thepercentage of fivefold numerals, and the rigidity of which side portionsis high, to be detached from the rim edge of the wheel not by manuallabor, but by a mechanical operation in a safe and efficient manner andthe same method.

BACKGROUND ART

[0002] The wheels of the vehicles for land transportation, on whichtires are directly mounted without filling a tube inside, prevail overin the market. The replacement of such tubeless tire as mentioned above,in which a tire is detached from the wheel, requires hard manual laborand higher skill on the part of the operators in comparison with thereplacement work of the tire with a tube filled inside, and is prone toinjure the operators. Thus, various types of tire replacement deviceshave been developed to date to lighten the burden on the part of theoperators as well as to secure their safety.

[0003] One example of such prior tire replacement devices is disclosedin Japanese Patent Registration No.2668318 entitled “Method fordetaching a tire of small nominal aspect ratio from the vehicle wheeland the same apparatus” in the name of the present inventor, whichmethod comprises the steps of fixing a wheel round which a tire isplaced on a certain turntable; compressing said tire from above so as toshove a tire bead into the setback portion of the wheel; inserting asteel lever between the tire bead and the rim edge of the wheel so as tosqueeze out of the wheel the tire bead and to hang the bead onto thebead suspender while at the same time to revolve the turntable so as todetach the tire bead from the wheel.

[0004] However, for its sporty appearance's sake, the recent passengercar tends to become short in height as if it touches the ground, due towhich, a tire whose nominal aspect ratio is below 50% and the rigidityof which side portions is extremely high becomes popular. If such tireof small nominal aspect ratio as mentioned above is detached from thewheel by such prior tire replacement device as mentioned above, it notonly requires hard labor on the part of the operators to squeeze out ofthe wheel a tire bead, but also it often occurs that a lever in use isdisplaced from the wheel so as to do damage on the latter or theoperators get injured, which prior issues are to be solved by thepresent invention.

DISCLOSURE OF THE INVENTION

[0005] In view of the above inconveniences encountered with the priorart and in order to solve such prior issues as mentioned above, thepresent invention is to provide an apparatus for detaching a tire fromthe vehicle wheel and the same method, which apparatus and method enablea bead of even the tire of such small nominal aspect ratio as mentionedabove, the rigidity of which side portions is high, to be detached fromthe rim edge of the wheel in a safe and efficient manner.

[0006] That is to say, the apparatus for detaching a tire from thevehicle wheel embodied in this invention is characterized in comprisinga turntable which rotates by a driving portion and on the top surface ofwhich a wheel, round which a tire is placed, is detachably mountable; anelevating rod disposed above said turntable such that it moves up anddown to a destination; a tire bead separation shoe comprising a wedgeportion to engage with a rim edge of the wheel so as to shove betweensaid rim edge and tire bead and a tire bead fold-back portion disposedadjacent to said wedge portion; a thrusting rod provided with a claw atits tip end portion to insert said claw between the tire bead and therim edge of the wheel and to squeeze out of the wheel the tire bead soas to move said bead onto the bead fold-back portion when the wedgeportion of said shoe is shoved between the tire bead and the rim edge ofthe wheel and a boom arrangement to make said thrusting rod squeeze outof the wheel the tire bead.

[0007] Then, the method embodied in the present invention with the aboveapparatus in use is characterized in comprising the steps of lowering anelevating rod with regard to the wheel round which a tire is placed andwhich is fixed on a turntable so as to engage a tire bead separationshoe with a rim edge of the wheel and to shove a wedge portion betweenthe rim edge of the wheel and the tire bead; operating a boomarrangement when said wedge portion is shoved between the tire bead andthe rim edge of the wheel so as to insert a claw of a thrusting rodbetween the tire bead and the rim edge of the wheel and to squeeze outof the wheel the tire bead and to move the bead onto the tire beadfold-back portion of said separation shoe while revolving the turntableso as to detach the tire bead from the whole circumference of the rimedge of the wheel.

[0008] Hereinafter, the best mode for carrying out the invention isdescribed in more details with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is the whole frontal view of the apparatus of the firstembodiment of the present invention to show its standby position;

[0010]FIG. 2 comprises a partly enlarged side view (a) of the tire beadseparation shoe of the above apparatus and a partly enlarged plan view(b) of the same;

[0011]FIG. 3 comprises the whole frontal view (a) of the above apparatusto show the first step of the method for detaching a tire from the wheeland a partly enlarged view (b) to show the movement of the tire beadseparation shoe and the thrusting rod of the same apparatus,respectively;

[0012]FIG. 4 comprises the whole frontal view (a) of the above apparatusto show the second step of the same method and a partly enlarged view(b) to show the movement of the tire bead separation shoe and thethrusting rod, respectively;

[0013]FIG. 5 comprises the whole frontal view (a) of the apparatus toshow the third step of the same method and a partly enlarged view toshow the movement of the tire bead separation shoe and the thrustingrod, respectively;

[0014]FIG. 6 is a perspective view to show the fourth step of the samemethod to rotate the turntable so as to detach the tire bead from thewhole circumference of the wheel rim edge and

[0015]FIG. 7 is a partly enlarged sectional view to show thecharacteristic parts of the apparatus of the second embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

[0016] (First Embodiment)

[0017] The apparatus of the present embodiment is shown in FIGS. 1 to 6.In the drawings, numeral 1 indicates a tire bead separation shoe andnumeral 2 indicates an elevating rod provided above a turntable R suchthat it moves up and down to a destination. This separation shoe 1 is anabutment member mounted at the lower end portion of the elevating rod 2and comprises a tire bead fold-back portion 11 to suspend a tire bead TBthereon in engagement with a rim edge WR of a wheel W which is fixed onthe turntable R and round which a tire T is placed and a wedge portion12 to shove between the tire bead TB and the rim edge WR in contact withthe former, which movements are shown in FIG. 2(a) and (b).

[0018] Numeral 3 in the drawings indicates a boom arrangement, andcomprises a boom 31 arranged such that it swings to a location in thecircumference of the turntable R; a back and forth moving rod 32provided at the top end side of said boom 31 such that it bends forwardsand a cylinder 33 provided at the top end side of said boom in parallelwith said rod 32 to impart a back-and-forth movement to said rod 32.

[0019] Numeral 4 in the drawings indicates a thrusting rod, which rod ismade from steel while working as a lever, and at the tip end portion ofwhich a claw 41 is provided.

[0020] Then, the operational steps taken by the apparatus of the presentembodiment to detach a tire bead from a wheel, round which a tire isplaced, are described below with reference to FIG. 1 as well as FIGS. 3to 6.

[0021]FIG. 1 shows the state immediately before a tire bead is detachedfrom the wheel, round which a tire is placed. In this state, theelevating rod 2 is lowered so that the separation shoe 1 provided at thelower end portion of the rod engages with the rim edge WR of the wheelW, round which the tire T is placed and which is fixed on the turntableR. In the meantime, the boom 31 is swung to a position as shown in FIG.3(a) and (b) so that it stands vertically with regard to the wheel whilethe claw 41 of the thrusting rod 4 axially supported on the top endportion of the boom arrangement 3 is abutted in between the rim edge WRof the wheel W and the tire bead TB so as to be shoved therebetween. Atthis stage, the backward movement of the rod 32 is constrained by astopper 34 such that the claw 41 keeps its appropriate position betweenthe rim edge WR and the tire bead TB.

[0022] Then, as shown in FIG. 4(a) and (b), the claw 41 engages with thetire bead TB by abutting the back surface of the claw 41 onto the wedgeportion 12 of the separation shoe 1 and extending the rod 32, whichportion 12 works as a lever of first order, while keeping the boom 31stand straight. It should be noted that the back and forth moving rod 32is provided with a cylinder 33, according to the back and forth movementof which cylinder, the former changes its posture and position asrequired.

[0023] Then, as shown in FIG. 5(a) and (b), the boom 31 is again swungand bent towards the wheel while keeping the rod 32 at its extendedposition. Correspondingly, the thrusting rod 4 slides through a holdingsleeve 32 a enclosing the former, and the back surface of the claw 41 ismounted into a guide groove 12 a of the wedge portion 12 as shown in thepartly enlarged view of FIG. 2(b), which groove works as a lever offirst order when said claw squeezes out of the wheel the tire bead TB soas to mount said bead onto the bead fold-back portion 11.

[0024] Finally, as shown in FIG. 6, when the driving portion D operatesso as to rotate said turntable R, the tire bead TB suspended onto thebead fold-back portion 11 is squeezed out over the rim edge WR of thewheel. When the turntable R rotates once, the tire bead TB surroundingthe whole circumference of the wheel is completely detached from the rimedge WR thereof.

[0025] (Second Embodiment)

[0026] Then, the apparatus of the present embodiment is shown in FIG. 7.The difference between the apparatus of the first embodiment and thisone lies in that a compression roller 5 is arranged in the diametricallyopposite side to the beam arrangement or thrusting rod when the claw 41squeezes out of the wheel the tire bead TB so as to mount the latteronto the bead fold-back portion 11. When the upper surface of a part ofthe tire T opposite to that of the tire into which the claw 41 is shovedis compressed down by said roller 5, this compression enforces the uppersurface thereof to be set back into a recessed portion of the wheel.This relaxes the tension applied to the tire bead TB, into which theclaw 41 is shoved, so that the claw is smoothly shoved into the tirebead TB, with the result that the efficiency of the operation improves.

[0027] The apparatus and the same method embodied in the presentinvention are substantially arranged as above, but the present inventionis not limited to the above embodiments and may be modified into variousmanners within the scope of the accompanying claims. For instance, inthe above embodiments, the thrusting rod 4 is axially supported at thetip end portion of the back-and-forth moving rod 32, but itsinstallation on the boom arrangement 3 is not limited to the top endportion thereof. It may be installed in various locations of the boomarrangement according to the modifications of the design. The apparatusembodied in the present invention may be either assembled integrallywith or attached to the existing tire replacement device, either ofwhich belongs to the technical scope of the present invention.

INDUSTRIAL APPLICABILITY

[0028] As described above, the present invention enables the bead ofeven a tire of small nominal aspect ratio or the ratio of whichsectional height to the sectional width thereof is small and therigidity of which side portions is high, to be automatically detachedfrom the vehicle wheel so as to improve on the safety and efficiency ofthe tire replacement work. Likewise, the thrusting rod to fold back thetire bead above the wheel rim edge takes the same trajectory course inuse all the time, so that there is no case where the thrust rod isdisplaced from the wheel in operation so as to do damage on the wheelsurface as in the prior art.

[0029] As mentioned above, the prior issues related to the conventionaltire replacement work are solved once and for all by the presentinvention, the structural arrangement of which is very simple, so thatits industrial applicability is very high.

1. An apparatus for detaching a tire (T) from a vehicle wheel (W)comprising a turntable (R) to rotate by means of a driving portion (D)and to detachably fix the wheel (W), round which the tire (T) is placed,thereon; an elevating rod (2) arranged above said turntable (R) suchthat it moves up and down to a destination; a tire bead separation shoe(1) mounted at the lower end portion of said elevating rod (2), whichshoe (1) comprises a wedge portion (12) to engage with a rim edge (WR)of the wheel (W) as fixed on the turntable (R) so as to shove betweenthe rim edge (WR) and a bead (TB) of said tire and a tire bead fold-backportion (11) provided adjacent to said wedge portion (12); a thrustingrod (4) provided with a claw (41) at its tip end portion, which claw(41) is shoved between said tire bead (TB) and rim edge (WR) of thewheel so as to squeeze out of the wheel the tire bead (TB) and to mountthe bead onto the tire bead fold-back portion (11), when the wedgeportion (12) of the tire bead separation shoe (1) is shoved between thetire bead (TB) and the rim edge (WR) of the wheel and a boom arrangement(3) to make the thrusting rod (4) squeeze out of the wheel (W) the tirebead (TB).
 2. An apparatus according to claim 1 wherein the boomarrangement (3) comprises a boom (31) arranged such that it swings to alocation in the vicinity of the turntable (R); a back-and-forth movingrod (32) arranged at a top end side of said boom (31) such that it bendsforwards; a cylinder (33) disposed at the top end side of said boom (31)in parallel with said back-and-forth moving rod (32), which cylinder(33) imparts a back and forth movement to said rod (32), wherein saidboom arrangement (3) allows the claw (41) axially supported on the tipend portion of the back and forth moving rod (32) to thrust between thewedge portion (12) and the tire bead (TB) as well as to squeeze out ofthe bead (TB) from the wheel (W).
 3. An apparatus according to claim 1or 2 wherein the back-and-forth moving rod (32) is slidably insertedinto a holding sleeve (32 a) fixed on the top end side of the boom (31)and said rod (32) moves back and forth according as said cylinder (33)advances and retracts.
 4. An apparatus in any one of the precedingclaims wherein the boom arrangement (3) is provided with a stopper (34)to constrain the retraction speed of the back-and-forth moving rod (32).5. An apparatus according to claim 3 wherein the thrusting rod (4) isaxially supported on the tip end portion of the cylinder (33) of theboom arrangement.
 6. An apparatus in any one of the preceding claimswherein a compression roller (5) is arranged in the diametricallyopposite side to the thrusting rod (4).
 7. An apparatus in any one ofthe preceding claims wherein a groove (12 a) to receive the claw (41) ofthe thrusting rod into is provided on the wedge portion (12) of the tirebead separation shoe (1) so that the claw is guided through the grooveupon penetration.
 8. A method for detaching a tire (T) from a vehiclewheel (W) comprising the steps of engaging a tire bead separation shoe(1) with a rim edge (WR) of the wheel by descending an elevating rod (2)with regard to the wheel, round which the tire is placed and which isfixed on a turntable (R) so as to shove a wedge portion (12) between therim edge and a tire bead (TB); operating a boom arrangement (3) when thewedge portion (12) is shoved between the tire bead (TB) and the rim edge(WR) of the wheel, wherein a claw (41) of a thrusting rod is shovedbetween the tire bead and the rim edge and the tire bead is squeezed outof the wheel so as to be mounted on a bead fold-back portion (11) of theseparation shoe while said turntable (R) is revolved so as to detach thewhole circumference of the tire bead (TB) from the rim edge (WR) of thewheel.